Centrifugal blasting machine



Nov. 21, 1944. R. E. PETERSON 2,363,437

CENTRIRUGAL BLASTING MACHINE Original Filed Sept. 9, 1940 2 Sheets-Sheet 1 1 9 2 f F 13. 1- 8 4 I INVENTOR 9041mm 5 P575/250N,

Nov. 21, 1944. R. E. PETERSON I CEN'I'RIFUGAL BLASTING MACHINE Original Filed Sept. 9, 1940 2 Sheets-Sheet 2 INV ENTOR @wm/vp E. PETERSON,

Patented Nov. 21, 1944 CENTRIFUGAL, BLASTING; MACHINE Rolland Peterson, Gary, Ind. I

I Continuation of application Serial No. 356,099, September'Q, 1940. This application June 14, 1943, Serial No. 490,823

6 Claims.

This invention relates to centrifugal blasting machines of the type used to produce a'blast of cation filed SeptemberQ, 1940, hearing Serial No.

Specific examples of theinvention' are illus-' trated by the accompanying drawings, in which: Figure 1 is a vertical, longitudinal section of a centrifugal blasting machine embodying the principles of the invention; I

Figure 2 is an enlargement from Figure 1; Figure 3 is a perspective of a detail from Figure 2;

Figure 4 is a crosssection fromthe line IV-IV in Figure 2; and

Figure 5 is' a view similar to showing a modification,

More specifically, the illustrated machine includes'a revolving series of fiat, radially centrifuging surfaces I, for the blast material, radiating Figure 2 but parallel with their revolving axis, in circumferential alignment, and with their radially extending ends,- at one end of theseries, provided with longitudinally extending, forwardly angling, longitudinally propelling surfaces 2 for the blast material. These surfaces 2 are'inclined to the revolving axis of the surfaces I, as contrasted to being parallel thereto as are the surfaces l. Means are provided for feeding a flow of blast material longitudinallyto said end of the series, this means comprising aplate 3 past which the ends 4 of the propelling surfaces 2 closely revolve and which is parallel with their circle of revolution. This plate has a plurality of orifices 5, 5a and 5b for ejecting the flow of blast material at a location in line between the side extremes 6 of the propelling surfaces 2, each orifice having an inlet connection 1 to which a conduit 8 is selectively applied, a constant flow of the blast material beingfed through this conduit 8 so as to selectively eject through one or'another of the orifices 5, 5a and 5b.

rial is fed to the propelling surfaces 2, the plate 3 being rotative to permit proper location of this In the normal operation of the machine, only a single flow of blast mate-' 5, 5a and 5b, at a velocity exceeding that of the flow, over the lengths of the centrifuging surfaces I, and to cause the latter to radially centrifuge the blast material therefrom. In machines of this type, embodying a relatively large number of centrifuging surfaces revolving at high speed, difliculty is encountered in completely loading the centrifuging surfaces, throughout their lengths, because the velocity of the flow of blast material is limited, by the nature of this material, to a value preventing its longitudinally flowing the lengths of the centrifuging surfaces, assuming they are of any substantial lengths, in the brief intervals during which the centrifuging surfaces revolve past the flow of blast material. This difiiculty is avoided in the case of the present invention in that the propelling surfaces 2 first engage the flow and, due to their angularity, propel the blast material 'lon gitudinally along the lengths of the plates at increased velocity, the increase in velocity effected depending on the angularity of the propelling surfaces 2 respecting the flow of blast material, for any given revolving speed. As a matter of fact, instead of the blast material never reaching the other ends of the centrifuging surfaces l a common occurrence in prior art machines, it is necessary to provide these other ends of the surfaces i, at the end of theseries opposite that to which the flow of material is fed, with forwardly extending retaining surfaces In for the blast material propelled by the. propelling surfaces 2. f V

A further feature is that the radially extending ends of the propelling surfaces 2, toward the flow of blast material, merge with oppositely facing, longitudinally extending, backwardly angling relief surfaces H for the blast material, which are behind the surfaces 2 and which Join with surfaces l2 opposite the centrifuging surfaces I, the propelling and centrifuging surfaces, 1 and 2, respectively, and their respectively opposite surfaces, II and i2, respectively, defining blade structures. These relief surfaces II are declined to the revolving axis andpermit free flow of blast material, unavoidably fed by the rear of each of the propelling surfaces 2, for reception by the next approaching propelling and centrifuging surfaces, as the various surfaces revoIve past the flow of blast material. The surfaces 2 and II completely merge, at the ends of the plates towardv the blast material, to form sharp edges which cut into the blast material without fragmentation of the-various abrasive particles constituting this material, while the backwardly angling surfaces ll provide room permitting the blast material to continue to feed. behind each propelling surface, onto the next approaching propelling surface. In some instances there may be deflection, such as when the revolving speeds are low compared to the velocity of the flow of blast material, the backwardly angling surfaces H then functioning as deflecting surfaces, laterally deflecting the material to the next approaching surfaces. In all events, there is an unimpeded flow of the blast material, so it is not knocked about and wasted as it is when it encounters fiat edges.

In the case of the illustrated machine, the various surfaces described are provided by a single cast, blade structure, the surface ill being formed by the forward face of a, circular disc Illa. This casting is set into a conventional centrifuging structure l3, providing the usual centrifuging surfaces withwhich the centrifuging surfaces I register, this structure I3 and the unit that has been disclosed being fixed relat ively immovable, and the structure, itself, being carried by the shaft end of the motor 9. The plate 3 works against the outer end of the structure I3 and may be sealed thereagainst, if desired, by a sliding seal H, the plate 3 being fixed to a tubular stub l5 rotating on astub shaft I6 positioned by a bracket II, the tubular stub l5 being capable of being locked against rotation by a set screw 1 8, this being necessary to lock the plate 3 against possible rotation with the centrifuging structure. Also, if desired, a housingl9 may be used, to cover the centrifuging structure IS, in the interest of safety. In Figure l the machine is shown as setover a conveyor 20 carrying a metal plate 2| past the machine for abrasive cleaning by the blast being created.

It has been explained that the surfaces I are useful in retaining the blast material propelled longitudinally over the centrifuging surfaces l by the propelling surfaces 2. The effect of the propelling surfaces 2 is so marked that the surfaces III are subject to erosion. To reduce erosion, and, incidentally, to produce a more concentrated blast pattern, when this is'desired, the arrangement shown by Figure may be resorted to. In this case, the centrifuging surfaces I radiate from a surface 22 which is circular about the revolving axis of the surfaces and which curvingly fiares longitudinally from the ends I of the propelling surfaces 2, where its radius from the revolving axis is materially less than that of the outer sidesof the centrifuging surfaces, to the latters opposite ends, where its radi-.

us from this axis is substantially the same as that of the outer sides of the centrifuging surfaces. This circular surface 22 extends the lengths of the propelling and centrifuging surfaces and provides, between the latter, radially deflecting surfaces for the blast material longitudinally propelled by the propelling surfaces 2. Since the blast material strikes these deflecting surfaces at an angle, erosion is reduced, while, as previously explained, there is an attendant effect of producing a more concentrated blast pattern. This blast pattern is also regulated by the shape of the flow of material initially fed to the propelling surfaces 2, the cross sectional contour of this flow being adjustable by the use of various ones of the orifices 5, 5a and 5b, which is possible by loosening the set screw I8, turning the plate 3 to bring the desired orifice into register with the conduit 8 and connecting this conduit to the conduit connection I of the orifice chosen, The apasoaasr parent reason, for this blast pattern control, s because the centrifuging force varies in proportion to the distance of the blast material from the centrifuging axis, whereby the pattern of a mass of blast material picked up from a fiow shape, like that provided by the orifice 5a, which is radially elongated respecting the centrifuging direction has this elongation increased, so an elongated blast pattern results, because the material farther from the axis receives more centrifuging force than material closer the axis and thus stretches the shape, while the flow resulting from the use of the orifice 5b provides for the effect of a larger proportion of the material being more equidistant from the axis so that less elongation occurs, with the orifice 5 providing for an intermeans for feeding a fiow of blast materialgenerally axially to said end of the series of blades at a speed causing the propelling surfaces to propel the blast material along the axis at a velocity exceeding that of thefiow and to cause the centrifuging surfaces to radially centrifuge the blast material therefrom.

2. A centrifugal blasting machine including a revolving series of flat, radial centrifuging blades having surfaces radiating parallel with their revolving axis in circumferential alignment and with their radially extending ends, at one end of the series, being provided with propelling surfaces which extend forwardly with respect to the direction of rotation and are inclined to said axis means for feeding a flow of blast material generally axially to said end of the series of blades at a speed causing the propelling surfaces to propel the blast material along the axis at a velocity exceeding that of the flow and to cause the centrifuging surfaces to radially centrifuge the blast material therefrom, the radially extending ends of the propelling surfaces merging with surfaces which extend backwardly from these ends with respect to the direction of rotation behind the propelling surfaces and which are declined to said axis so as to provide clearance for blast material unavoidably fed to the rear of each propelling surface.

3. A centrifugal blasting machine including a revolving series of flat, radial centrifuging blades having surfaces radiating parallel with their revolving axis in circumferential alignment and with their radially extending ends, at one end of the series, being provided with propelling surfaces which extend forwardly with respect to the direction of rotation and are inclined to said axis; means for feeding a flow of blast material generally axially to said end of the series of blades at a speed causing the propelling surfaces to propel the blast material along the axis at a velocity exceeding that of the flow and to cause the centrifuging surfaces to radially centrifuge the blast material therefrom, the means for feeding the flow of blast material including a plate past which the radially extending ends of the propelling surfaces closely revolve and which is parallel with their circle of revolution, this plate having an orifice for ejecting the flow of blast material at a location between the axially extending side extremes of the propelling surfaces.

4. A centrifugal blasting machine including a revolving series of flat, radial centrifuging blades having surfaces radiating parallel with their revolving axis in circumferential alignment and with their radially extending ends, at one end of the series, being provided with propelling surfaces which extend forwardly with respect to the direction of rotation and are inclined to said axis; means for feeding a flow of blast material generally axially to said end of the series of blades at a speed causing the propelling surfaces to propel the blast material along the axis at a velocity exceeding that of the flow and to cause the centrifuging surfaces to radially centrifuge the blast material therefrom, the means for feeding the flow of blast material including means for controlling the cross-section contour of the flow of blast material fed thereby.

5. A centrifugal blasting machine including a revolving series of flat, radial centrifuging blades having surfaces radiating parallel with their revolving axis in circumferential alignment and with their radially extending ends, at one end of the series, being provided with propelling surfaces which extend forwardly with respect to the direction of rotation and are inclined to said axis; means for feeding a flow of blast material to cause the centrifuging surfaces to radially,

centrifuge the blast material therefrom, the other radially extending ends of the surfaces, at the end of the series opposite that to which the flow of material is fed, having retaining surfaces for the blast material propelled by the propelling surfaces which extend forwardly with respect to the direction of rotation at an angle to said axis.

6. A centrifugal blasting machine including a revolving series of flat, radial centrifuging blades having surfaces radiating parallel with their revolving axis in circumferential alignment and with their radially extending ends, at one end of the series, being provided with propelling surfaces which extend forwardly with respect to the direction of rotation and are inclined to said axis; means for feeding a flow of blast material generally axially to said end of the series of blades at a speed causing the propelling surfaces to propel the blast material along the axis at a velocity exceeding that of the now and to cause the centrifuging surfaces to radially centrifuge the blast material therefrom, the centrifuging surfaces radiating from a surface which is circular about the revolving axis of the surfaces and which curvingly flares axially from the radially extending ends of the propelling surfaces, where its radius from said axis is materially less than that of the axially extending sides of the centrifuging surfaces remote from said axis, to their opposite radially extending ends where its radius from said axis is substantially increased, this circular surface extending along the axially ex: tending lengths of the centrifuging surfaces and providing, between the latter, radially deflecting surfaces for the blast material axially propelled by the propelling surfaces.

ROLLAND E. PETERSON. 

